York AC sour smell, proper UV light positioning near coils

by Warren W
(Brandon, FL)

Rust on coils & lower pan

Closeup of coil rust

UV light mounted in the AC unit

AIr box out of level away from drain

March 2, 2011

I live in Florida and have an attic installed air-handler, which is a horizontal left facing air handler. The central ac unit is just under 2 years old, York YZH048 3.5-4.0 Ton 17 SEER Affinity air conditioner system, with an AVY048 variable speed air handler with RX coil.

Over the winter, I noticed a sour smell coming from the home air ducts when the heat was on, and again as the weather warmed up, when I turned it to cool for the first time in 2 weeks. We contacted the installation company and they sprayed the coils off with some sort of de-sting and taped up the access cover to limit any possible outside air sources.

The AC tech also recommended that I ALWAYS run my fan 24/7 to help eliminate the problem in the future. After removing the AC filter and inspecting the coils with a mirror, I found rust on the 2-yr coil frame and the UV light located away from the coil A-frame.

I have no other sour attic smell or sour smell near the returns. Is the coil the source of the smell? Should there be rust on the coil frame and should I always run my blower which draws approx the same wattage as a 100 w light bulb.

Is the Honeywell UV light (SIUV100A208) in the correct location to control coil growth? Any assistance would be appreciated.

The contractor that installed the unit, Brandon Air, replaced the evaporator coils and had the new coils specially dipped in a mildewcide solution. No smell as of 6 months. I have read or other reports where the manufacture will not assist, I believe that York did not pay for the replacement or the special dipping and the cost was through our warranty with Brandon Air. I wish I had a quick and easy solution for you. Good Luck.